A fully photonics-based coherent radar system
A fully photonics-based coherent radar system
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DOI：
10.1038/nature13078
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发表时间：
2014-03-20
期刊：
影响因子：
64.8
通讯作者：
Bogoni, Antonella
中科院分区：
文献类型：
--
作者：
Ghelfi, Paolo;Laghezza, Francesco;Bogoni, Antonella
下一代雷达（无线电探测和测距）系统需要基于软件定义无线电以适应各种环境，更小的天线具有更高的载波频率，更宽的带宽以提高分辨率（1-4）。今天的数字微波组件（合成器和模数转换器）在增加的频率（5-7）下受到有限带宽和高噪声的影响，因此全数字雷达系统只能工作在几千兆赫兹，并且有噪声的模拟上变频和下变频对于更高的频率是必要的。相比之下，光子学提供了高精度和超宽带宽（8，9），允许灵活地生成具有任意波形（高达毫米波）的极其稳定的射频信号（10-22），以及检测此类信号及其精确的直接数字化而无需下变频（23-26）。到目前为止，基于光子学的射频信号的产生和检测已经被单独研究，并且尚未在雷达系统中进行测试。在这里，我们提出了一个完全基于光子学的相干雷达演示器的项目PHODIR 27内进行的开发和现场试验结果。所提出的架构利用单个脉冲激光器来产生可调谐雷达信号并接收其回波，避免射频上变频和下变频，并保证软件定义的方法和高分辨率。其性能超过了载波频率在2千兆赫以上的最先进的电子设备，对不合作飞机的探测证实了该系统的有效性和预期精度。
The next generation of radar (radio detection and ranging) systems needs to be based on software-defined radio to adapt to variable environments, with higher carrier frequencies for smaller antennas and broadened bandwidth for increased resolution(1-4). Today's digital microwave components (synthesizers and analogue-to-digital converters) suffer from limited bandwidth with high noise at increasing frequencies(5-7), so that fully digital radar systems can work up to only a few gigahertz, and noisy analogue up-and downconversions are necessary for higher frequencies. In contrast, photonics provide high precision and ultrawide bandwidth(8,9), allowing both the flexible generation of extremely stable radio-frequency signals with arbitrary waveforms up to millimetre waves(10-22), and the detection of such signals and their precise direct digitization without downconversion(23-26). Until now, the photonics-based generation and detection of radio-frequency signals have been studied separately and have not been tested in a radar system. Here we present the development and the field trial results of a fully photonics-based coherent radar demonstrator carried out within the project PHODIR27. The proposed architecture exploits a single pulsed laser for generating tunable radar signals and receiving their echoes, avoiding radio-frequency up-and downconversion and guaranteeing both the software-defined approach and high resolution. Its performance exceeds state-of-the-art electronics at carrier frequencies above two gigahertz, and the detection of non-cooperating aeroplanes confirms the effectiveness and expected precision of the system.